add checks for missing return statement

[r19916]

diff --git a/parser.c b/parser.c
index 198ca6b..531d07f 100644 (file)
--- a/parser.c
+++ b/parser.c
@@ -4314,6 +4314,64 @@ static void check_declarations(void)
        }
 }
 
+/**
+ * check all returns vor matching type.
+ */
+static bool search_return_statements(statement_t *statement) {
+       switch(statement->kind) {
+       case STATEMENT_RETURN:
+               /* ok, found a return */
+               return true;
+       case STATEMENT_IF: {
+               /* return must be found on then and else */
+               if_statement_t *if_stat = &statement->ifs;
+               if(if_stat->true_statement != NULL && if_stat->false_statement != NULL) {
+                       return search_return_statements(if_stat->true_statement) &&
+                              search_return_statements(if_stat->false_statement);
+               }
+               break;
+       }
+       case STATEMENT_DO_WHILE: {
+               do_while_statement_t *do_stmt = &statement->do_while;
+               if(do_stmt->body != NULL) {
+                       if (search_return_statements(do_stmt->body))
+                               return true;
+               }
+               break;
+       }
+       case STATEMENT_COMPOUND: {
+               /* search the last statement */
+               compound_statement_t *compound = &statement->compound;
+               statement_t *statement = compound->statements;
+               if(statement == NULL)
+                       return false;
+               for( ; statement != NULL; statement = statement->base.next) {
+                       if (search_return_statements(statement))
+                               return true;
+               }
+               break;
+       }
+       default:
+               break;
+       }
+       return false;
+}
+
+/**
+ * Check returns of a function.
+ */
+static void check_return_type(declaration_t *declaration) {
+       function_type_t *function_type = &declaration->type->function;
+       type_t          *ret_type      = function_type->return_type;
+
+       if (ret_type != type_void) {
+               if (! search_return_statements(declaration->init.statement)) {
+                       warningf(HERE, "missing return statement at end of non-void function '%Y'",
+                                       declaration->symbol);
+               }
+       }
+}
+
 static void parse_external_declaration(void)
 {
        /* function-definitions and declarations both start with declaration
@@ -4425,6 +4483,7 @@ static void parse_external_declaration(void)
                assert(current_function == declaration);
                current_function = old_current_function;
                label_pop_to(label_stack_top);
+               check_return_type(declaration);
        }
 
 end_of_parse_external_declaration: